Pekin Duck not Quacking

I have searched everywhere for the answer to this question, the closest info I can find is a duck that could quack and then lost its quack my duck has never quacked. I have 2 Pekin ducks, when purchased they were supposedly already sexed and they are both females, they are both around 8 weeks old. My one Pekin (Louise) quacks very loudly, but my other Pekin (Thelma) she has NEVER quacked, she only peeps. Will she ever quack?? Any info would be greatly appreciated! They are both very sweet ducks, but Thelma (my non quacker) seems more dominate towards our Turkeys. ~TIA

Welcome to BYC! I have somewhat limited experience in waterfowl, but my guess would be that Thelma may be a male. Drakes lack the characteristic loud "quack", are a lot quieter, and make a sort of low "meep" sound. At one time, I had a Rouen and a Runner drake that would chase my two toms around too. So a sexing mistake would be my guess.